1. Field of the Invention
The present invention relates to systems and techniques for guiding steering and advancing invasive medical devices such as catheter and catheter-type devices in a patient while using a radar system to determine the location of the catheter within the patient.
2. Description of the Related Art
Catheterization is typically performed by inserting an invasive device into an incision or a body orifice. Secondary tools such as guidewires and balloons are often advanced along the catheter to the area where the medical procedure is to be performed. These procedures rely on manually advancing the distal end of the invasive device by pushing, rotating, or otherwise manipulating the proximal end that remains outside of the body. Real-time X-ray imaging is a common method for determining the position of the distal end of the invasive device during the procedure. The manipulation continues until the distal end reaches the destination area where the diagnostic or therapeutic procedure is to be performed. This technique requires great skills on the part of the surgeon/operator. Such skill can only be achieved after a protracted training period and extended practice. A high degree of manual dexterity is also required.
Because of the difficulty involved in advancing a catheter into a desired location in the body, many diagnostic and therapeutic procedures often employ a guidewire. The guidewire is first advanced into the heart or the artery and serves as a track and guide for a specific catheter. For example, this technique is used to advance a catheter into the left ventricle and is especially important when studying aortic stenosis. Crossing the narrowed valve orifice is a challenge to the operator. Similarly, a guidewire is often manipulated into a blocked coronary artery and across the obstructive plaque. A therapeutic catheter, carrying, for example a balloon, a laser, a stent, etc., is advanced over the guidewire, and placed at the site of the plaque. The narrowed site is then opened by inflating a balloon, operating a laser beam, or placing a stent. On occasions, the artery is torturous and severely narrowed and the plaque is irregular, calcified, or even totally occluding the artery. In these situations the placement of a guidewire beyond the narrowed site is very difficult and many times unsuccessful.
Therefore, there is a substantial and unsatisfied need for an apparatus and method for guiding, steering, advancing and locating the position of invasive devices and for accurately controlling their position; for providing three dimensional imaging; and for minimizing the use of X-rays or other ionizing-type radiation